In the digital arts there are several areas that you could explore, from animation to film with digital cameras, but one of the most interesting one would be digital design, since it is how most of the work in design is done nowadays and that would be a terrific area of the digital arts to start exploring further to approach the digital arts in a different ways, since when you learn design you also learn a lot of techniques and ruler to make things prettier.
The answer is D. They are realistic and show the American West. The reason is because, well, that is what Albert Bierstadt painted. Albert was from Germany, but he made several journeys to the west and made paintings of what he saw.